I've used the Serostim. Like they said, if you use bacteriostatic water instead of the sterile water that came with it, it will last at least 14 days. To make your own bacteriostatic water just go to the grocery store and buy some DISTILLED WATER. Add 1 ML of Benzyl Alcohol for every 99 ML of Distilled water. Then filter it through a 22um syringe filter (vialsandcrimpers.com has them). That's all there is to making bacteriostatic water. Mix 1 ML of bac. water with the little vial of GH. Shoot the water down the side of the vial, not directly on the wafer/powder. Using an insulin syringe (3/10cc is the easiest to read), 5.5 = 1iu, 11 = 2iu, etc. You can buy the syringes at Walmart for about $13 per box of 100. (get their generic brand [Reli-On]) Just for your information, the 18iu vial w/ the sterile water is used for aids patients. They take all 18iu each day. Most people here will probably recommend 4-6iu's per day. I get by on 2iu's per day. Your budget has a lot to due with the dosage. Also, the side effects will dictate your dose. If you are taking too much, you will have extremely sore joints ie. carpal tunnel syndrome. Hope this helps.